METHOD FOR EXTRACTING CONTAMINANTS FROM AGRARIAN PRODUCTS AND APPARATUS THEREFOR

Abstract

In a method for extracting contaminants from agrarian products or foods or animal feeds containing agrarian products, comprising contacting a solvent for the contaminants with the agrarian products containing or having adsorbed the contaminants, or the foods or animal feeds, and at least one extraction buffer in an optionally closable mixing vessel, the extraction buffer, which is contained in a film soluble in the solvent and is supplemented with at least one surfactant, in particular nonionic surfactant, and the contaminated agrarian product or food or animal feed are contacted with cold water as solvent in the mixing vessel, and the extraction buffer and the contaminants are brought into solution by agitating or stirring in the mixing vessel; and apparatus therefor.

Claims

1. A method for extracting contaminants from agrarian products or foods or animal feeds containing agrarian products, comprising contacting a solvent for the contaminants with the agrarian products containing or having adsorbed the contaminants, or the foods or animal feeds, and at least one extraction buffer, and optionally a powdery carrier, in an optionally closable mixing vessel, wherein the extraction buffer, which is contained in a film soluble in the solvent and is supplemented with at least one surfactant, in particular nonionic surfactant, and the contaminated agrarian product or food or animal feed are contacted with cold water as solvent in the mixing vessel, and the extraction buffer and the contaminants are brought into solution by agitating or stirring in the mixing vessel.

2. The method according to claim 1, wherein water having a temperature between 8 C. and 25 C., in particular distilled water, is used.

3. The method according to claim 1, wherein at least one buffer selected from the group consisting of borate buffers having a pH of 8.5, carbonate buffers having a pH of 9.1, citrate buffers having a pH of 7.1, phosphate buffers having a pH of 7.4 and Tris/HCl buffer having a pH of 7.4 is used as extraction buffer.

4. The method according to claim 1, wherein the extraction buffer is used at a concentration of between 10 mM and 100 mM.

5. The method according to claim 1, wherein 0.1 to 1% of a surfactant is added to the extraction buffer.

6. The method according to claim 1, wherein an inert silicate powder such as high-purity silicic acid is used as said powdery carrier.

7. The method according to claim 6, wherein the surfactant is selected from polyoxyethyelene lauryl ether (Brij 35), polyoxyethylene acetyl ether (Brij 58), 4-(1,1,3,3-tetramethylbutyl-polyethylene glycol (Triton X100), (1,1,3,3-tetramethylbutyl)phenyl-polyethylene glycol (Triton X114), polysorbate 20, polysorbate 80 or sodium dodecyl sulfate.

8. The method according to claim 1, wherein the film soluble in the solvent is used as a bag closed on all sides and containing a buffer comprising at least two of the following components: sodium or potassium salts of boric acid, carboxylic acid, citric acid, phosphoric acid, phosphorous acid, TRIS (Tris(hydroxymethyl)-aminomethane) and NaCl, said buffer after dissolution having a molarity of 6 to 250 mM, in particular 10 to 100 mM, and a pH ranging from 6.5 to 9.5, in particular between 7.1 and 9.1.

9. A device for extracting contaminants from agrarian products or from the surfaces of agrarian products, or foods or animal feeds containing agrarian products, including an optionally closable mixing vessel, wherein the mixing vessel is comprised of a foldable plastic bag containing an extraction buffer enclosed in a soluble, in particular water-soluble, film.

10. The device according to claim 9, wherein the plastic bag is closed by welds comprising, in particular on one end, a tear-open element, and that the extraction buffer enclosed in the water-soluble film is received in the closed plastic bag.

11. The device according to claim 9, wherein one end of the plastic bag is formed with a double bottom, and that the film facing the interior of the plastic bag and forming said double bottom of the plastic bag is comprised of the water-soluble film enclosing the extraction buffer.

12. The device according to claim 9, wherein the tear-open element is designed as a plastic rod, in particular stirring rod.

13. The device according to claim 9, wherein the plastic bag comprises a scale in a manner known per se.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In the following, the invention will be explained in more detail by way of exemplary embodiments illustrated in the drawing. Therein,

[0023] FIG. 1 illustrates a device according to the invention containing an extraction buffer enclosed in a water-soluble film;

[0024] FIG. 2 illustrates another configuration of the device of FIG. 1, in which the extraction buffer is provided in the double bottom of a plastic bag; and

[0025] FIG. 3 depicts the device of FIG. 1 in the opened state, when in use.

DETAILED DESCRIPTION OF THE INVENTION

[0026] In detail, FIG. 1 illustrates a mixing vessel comprised of a plastic bag 1, in whose interior an extraction buffer 3 received in a water-soluble film 2 is contained. The extraction buffer can be supplemented with high-purity silicic acid as a carrier so as to improve its filling and homogenization, yet without influencing its extraction properties. In the illustration according to FIG. 1, the bag 1 is shown in the closed state with a tear-open element 4 provided on its upper end, in which a rod-shaped element 5 is enclosed, which rod-shaped element 5 is also torn off when opening the bag 1 and can subsequently be removed from the torn-off part of the tear-open element 4 and, for instance, be used as a stirring rod. The bag 1, moreover, comprises a scale 6 on its outer side to enable the determination of the exact amount of water to be filled in when in use.

[0027] FIG. 2 depicts another variant of a device according to the invention, in which the reference numerals have been retained as far as possible. The bag 1 is again provided with a scale 6, and on its upper end additionally comprises a tear-open element 4 designed as a tear-open edge 4. In the illustration according to FIG. 2, the tear-open element 4 is provided with a perforation 7, whereby, when opening the bag 1, the bag 1 can be opened by simply pulling off the upper tear-open element 4 along said perforation 7. The lower region of the bag 1 is, moreover, formed with a double bottom 8, the extraction buffer 3 being enclosed between the lower end of the bag 1 and the double bottom 8. In use, such a bag 1 is opened, water is filled in as far as to the desired mark, and the soluble film 2 covering the extraction buffer 3 as a double bottom 8 is dissolved either by careful shaking of the bag or by stirring in the interior of the bag, thus causing the buffer to come into contact with the solvent. After the extraction buffer 3 has been dissolved, the agrarian product 9 to be examined is filled into the interior of the bag 1 and either allowed to rest for some minutes or further stirred in order to detach as rapidly as possible the contaminants contained on the surface of the product 9. It goes without saying that the agrarian product and the buffer to be dissolved can be filled in simultaneously or in any order. After this, it will do to detect, for instance by a strip test, whether, or in the case of a quantitative strip test what amounts and/or kinds of, contaminants or mycotoxins were present on the surface of the agrarian product 9.

[0028] FIG. 3 depicts the bag 1 of FIG. 1, illustrating the bag in the torn-open state with the extraction buffer 3 already dissolved, the water-soluble film 2 already showing cracks and destructions, and the agrarian product 9 to be examined having, moreover, been filled in along with water as solvent. For dissolving, or facilitating the dissolution of, the extraction buffer 3 and detaching the contaminants from the surface of the agrarian product 9, the stirring rod 5 is used for stirring in the interior of the bag 1.

[0029] After the complete dissolution of the extraction buffer 3, a conventional strip test can, for instance, be used to examine the presence of contaminants.

Example 1

Detection of Different Mycotoxins in Maize Samples

[0030] The Tables below show the detection of different mycotoxins in maize samples when tested with different buffers comprising salts and surfactants, and a summary of the detection of toxins in the phosphate buffer system (each at concentrations of 10 mM and 100 mM), performed with ELISA: [0031] carbonate buffer, pH 8.5 [0032] carbonate buffer, pH 9.1, [0033] citrate buffer, pH 7.1, [0034] phosphate buffer, pH 7.4 and [0035] Tris/HCl buffer, pH 7.5.

[0036] In the Tables, the following detection ratios are indicated:

TABLE-US-00001 Results of strip tests (LFDs): Result Detection (+) .sup.<30% + 30-50% ++ 50-80% +++ .sup.>80%

Aflatoxins:

[0037] Table 1 shows the detection of aflatoxins in maize samples. Different buffer combinations (salt+surfactant) were tested.

TABLE-US-00002 TABLE 1 Aflatoxins Tween Tween Triton Triton Brij Brij 20 80 X100 X114 35 58 SDS [%] [%] [%] [%] [%] [%] [%] Buffer [mM] 0.1/1 0.1/1 0.1/1 0.1/1 0.1/1 0.1/1 0.1/1 Borate ++/++ ++/+++ ++/++ ++/+++ ++/++ ++/+++ +++/++ 10 mM Borate ++/++ ++/++ ++/++ ++/++ ++/++ ++/++ +++/++ 100 mM Carbonate ++/+++ ++/+++ ++/++ ++/+++ ++/++ ++/+++ +++/++ 10 mM Carbonate ++/+++ ++/+++ ++/++ ++/+++ ++/++ ++/++ +++/++ 100 mM Citrate +/+ +/++ +/++ +/++ +/++ +/++ ++/+ 10 mM Citrate +/+ +/+ +/+ +/+ +/+ +/+ ++/+ 100 mM Phosphate ++/+++ ++/+++ ++/++ ++/++ ++/+++ ++/+++ +++/++ 10 mM Phosphate ++/+++ ++/++ ++/++ ++/++ ++/+++ ++/+++ +++/++ 100 mM Tris/HCl ++/++ ++/++ ++/++ ++/++ ++/++ ++/++ +++/++ 10 mM Tris/HCl ++/++ ++/++ ++/++ ++/++ ++/++ ++/++ +++/++ 100 mM

Deoxynivalenol:

[0038] Table 2 shows the detections of deoxynivalenol in maize samples. Different buffer combinations (salt+surfactant) were tested.

TABLE-US-00003 TABLE 2 Deoxynivalenol Tween Tween Triton Triton Brij Brij 20 80 X100 X114 35 58 SDS Buffer [%] [%] [%] [%] [%] [%] [%] [mM] 0.1/1 0.1/1 0.1/1 0.1/1 0.1/1 0.1/1 0.1/1 Borate +++/+++ +++/+++ +++/+++ +++/+++ +++/+++ +++/+++ +++/++ 10 mM Borate +++/+++ +++/+++ +++/+++ +++/+++ +++/+++ +++/+++ +++/++ 100 mM Carbonate +++/+++ +++/+++ +++/+++ +++/+++ +++/+++ +++/+++ +++/++ 10 mM Carbonate +++/+++ +++/+++ +++/+++ +++/+++ +++/+++ +++/+++ +++/++ 100 mM Citrate ++/++ ++/++ ++/++ ++/++ ++/++ ++/++ ++/+ 10 mM Citrate ++/++ ++/++ ++/++ ++/++ ++/++ ++/++ ++/+ 100 mM Phosphate +++/+++ +++/+++ +++/+++ +++/+++ +++/+++ +++/+++ +++/++ 10 mM Phosphate +++/+++ +++/+++ +++/+++ +++/+++ +++/+++ +++/+++ +++/++ 100 mM Tris/HCl +++/+++ +++/+++ +++/+++ +++/+++ +++/+++ +++/+++ +++/++ 10 mM Tris/HCl +++/+++ +++/+++ +++/+++ +++/+++ +++/+++ +++/+++ +++/++ 100 mM

Fumonisins:

[0039] Table 3 shows the detections of fumonisins in maize samples. Different buffer combinations (salt+surfactant) were tested.

TABLE-US-00004 TABLE 3 Fumonisins Tween Tween Triton Triton Brij Brij 20 80 X100 X114 35 58 SDS [%] [%] [%] [%] [%] [%] [%] Buffer [mM] 0.1/1 0.1/1 0.1/1 0.1/1 0.1/1 0.1/1 0.1/1 Borate ++/+++ ++/+++ ++/+++ ++/+++ ++/(+) ++/(+) ++/(+) 10 mM Borate ++/+++ ++/+++ ++/+++ ++/+++ ++/(+) ++/(+) ++/(+) 100 mM Carbonate ++/+++ ++/+++ ++/+++ ++/+++ ++/(+) ++/(+) ++/(+) 10 mM Carbonate ++/+++ ++/+++ ++/+++ ++/+++ ++/(+) ++/(+) ++/(+) 100 mM Citrate ++/++ ++/++ ++/++ ++/++ ++/(+) ++/(+) ++/(+) 10 mM Citrate ++/++ ++/++ ++/++ ++/++ ++/(+) ++/(+) ++/(+) 100 mM Phosphate ++/+++ ++/+++ ++/+++ ++/+++ ++/(+) ++/(+) ++/(+) 10 mM Phosphate ++/+++ ++/+++ ++/+++ ++/+++ ++/(+) ++/(+) ++/(+) 100 mM Tris/HCl ++/+++ ++/+++ ++/+++ ++/+++ ++/(+) ++/(+) ++/(+) 10 mM Tris/HCl ++/+++ ++/+++ ++/+++ ++/+++ ++/(+) ++/(+) ++/(+) 100 mM

Zearalenones:

[0040] Table 4 shows the detections of zearalenones in maize samples. Different buffer combinatione (salt+surfactant) were tested.

TABLE-US-00005 TABLE 4 Zearalenone: Tween Tween Triton Triton Brij Brij 20 80 X100 X114 35 58 SDS [%] [%] [%] [%] [%] [%] [%] Buffer [mM] 0.1/1 0.1/1 0.1/1 0.1/1 0.1/1 0.1/1 0.1/1 Borate +++/++ +++/++ +++/++ +++/++ +++/++ +++/++ +++/+ 10 mM Borate +++/++ +++/++ +++/++ +++/++ +++/++ +++/++ +++/+ 100 mM Carbonate ++/+++ ++/+++ +++/++ ++/+++ +++/++ ++/+++ +++/+ 10 mM Carbonate ++/+++ ++/+++ +++/++ ++/+++ +++/++ ++/+++ +++/+ 100 mM Citrate +/+ +/+ +/+ +/+ +/+ +/+ ++/+ 10 mM Citrate +/+ +/+ +/+ +/+ +/+ +/+ ++/+ 100 mM Phosphate +++/++ +++/++ +++/++ +++/++ +++/++ +++/++ +++/+ 10 mM Phosphate +++/++ +++/++ +++/++ +++/++ +++/++ +++/++ +++/+ 100 mM Tris/HCl ++/+++ ++/+++ ++/+++ ++/+++ +++/++ ++/+++ +++/+ 10 mM Tris/HCl ++/+++ ++/+++ ++/+++ ++/+++ +++/++ ++/+++ +++/+ 100 mM

TABLE-US-00006 TABLE 5 Summary of LFD results: Tween Tween Triton Triton Brij Brij 20 80 X100 X114 35 58 TOXIN [%] [%] [%] [%] [%] [%] SDS [%] PBS buffer 0.1/1 0.1/1 0.1/1 0.1/1 0.1/1 0.1/1 0.1/1 Aflatoxins ++/++ ++/++ ++/++ ++/++ ++/+++ ++/++ +++/+ 10 mM Aflatoxins ++/++ ++/++ ++/++ ++/++ ++/+++ ++/++ +++/+ 100 mM Deoxynivalenol +++/+ +++/+ +++/++ +++/+ +++/++ +++/+ +++/+ 10 mM Deoxynivalenol +++/+ +++/+ +++/++ +++/+ +++/++ +++/+ +++/+ 100 mM Fumonisins ++/++ ++/++ ++/+++ ++/++ ++/(+) ++/(+) ++/(+) 10 mM Fumonisins ++/++ ++/++ ++/+++ ++/++ ++/(+) ++/(+) ++/(+) 100 mM Zearalenones ++/+++ +++/+ +++/++ +++/+ +++/++ ++/+ +++/+ 10 mM Zearalenones ++/+++ +++/+ +++/++ +++/+ +++/++ ++/+ +++/+ 100 mM

[0041] It follows from the above Tables that the LFD and ELISA results are comparable, and the different buffer systems and different surfactants and concentrations are applicable to the extraction method, yielding reliable results.

Example 2

Extraction of Food Allergens using an Extraction Buffer Contained in Water-Soluble Films

[0042] Tris/HCl and a PBS buffer, each shrink-wrapped in a water-soluble film, are introduced into a plastic container and supplemented with cold tap water until 100 mM, 150 mM, 200 mM and 250 mM solutions have each formed. The solutions had pH values ranging between 6.5 and 8.8 as a function of the employed buffer.

[0043] Both extraction buffers enabled the quantitative extraction of the following food allergens, using all four different concentrations: -lactoglobulin, casein, cashew nut, egg white, peanut, fish, hazelnut, crustaceans, lupin, almond, milk, ovalbulmin, pistachio, mustard, sesame, soy, walnut.

Example 3

Extraction of Genetically Modified Organism using an Extraction Buffer Contained in Water-Soluble Films

[0044] Tris/HCl, PBS and a borate buffer, each shrink-wrapped in a water-soluble film along with Tween or Triton and silicagel, are introduced into a plastic container and supplemented with cold tap water until 100 mM, 150 mM, 200 mM and 250 mM solutions have each formed.

[0045] Both extraction buffers enabled the quantitative extraction of the following genetically modified organisms, and the quantification of the results by Statfax and Chromate readers, using all four different concentrations: RUR, Cry1F, Cry1AB, Cry3bb, LL, Cry34AB1, VIP, Btk, BR, B2R, EPSPS, DAS Cry1Ac.